The present invention relates to an improved distribution system for use in a pastillation machine, and more particularly, a distribution system that provides for an essentially even distribution of a flowable substance at the outlet thereof.
Pastillation machines typically include an inner cylinder that receives a flowable substance from a source. An outer cylinder rotates about the inner cylinder and has rows of openings formed therein. The flowable substance is delivered under pressure from the inner cylinder, through the rows of openings in the outer cylinder. The flowable substance is then dropped onto a moving conveyor device and cooled to form hemispherical pastilles. Pastillation machines are particularly useful for forming elemental sulphur and sulphur based fertilizer pastilles.
A distribution bar for a machine for extruding flowable substances is disclosed in U.S. Pat. No. 4,623,307 to Froeschke. The distribution bar is located in a groove that is formed in the outer surface of the inner cylinder of the machine. The distribution bar has a series of inlet holes that receive the flowable substance from the inner cylinder. The flowable substance passes through these inlet holes into an elongated slot that is formed along the length of the distribution bar. The slot is located adjacent to the inner wall of the outer cylinder. The holes of the distribution bar are placed very close together in an attempt to distribute the flowable substance evenly within the elongated slot of the distribution bar.
Even distribution of the flowable substance is an important consideration, in order for the flowable substance to be forced out through the holes of the outer cylinder evenly and thus, to form pastilles that are similar in size. The many holes in the distribution bar of the prior art are subject to clustering and agglomeration of the flowable substance, which results in product of inferior quality and inconsistent sizing. The holes also require frequent cleaning in order to minimize the clustering and agglomeration of the flowable substance, which results in increased equipment downtime.
Pasitllation machines typically operate at high temperatures in order to keep the hot liquid flowable. At such temperatures, the distribution bar is subjected to heat stress, which may cause the distribution bar to lose its seal with the flowable substance inlet holes. In addition, warping of the distribution bar causes uneven wear, particularly on the surface of the distribution bar that is in constant contact with the rotating outer cylinder. More importantly, the warped distribution bar may score the outer cylinder. The outer cylinder is an expensive component to replace and therefore any unnecessary wear on the outer cylinder is undesirable.
It is therefore an object of an aspect of the present invention to provide a distribution system that improves the distribution of the flowable substance at an outlet thereof.
According to one aspect of the present invention there is provided in a pastillation machine, an improved distribution system for a flowable substance to be formed into pastilles. The distribution system comprises: a bar having a bore extending therethrough, a series of holes located on an inlet surface of the bar, a series of slots located on an outlet surface of the bar, and a diffuser located in the bore of the bar, the diffuser being spaced between the inlet surface and the outlet surface wherein the series of holes is aligned with flowable substance outlets of the pastillation machine.
According to another aspect of the present invention there is provided a diffuser for a distribution system for use in a pastillation machine. The diffuser comprises: an elongate body sized to fit into a bore of the distribution bar, and a centering device coupled to the elongate body for engaging at least one surface of the bore of the distribution bar wherein the centering device maintains the elongate body generally spaced from at least one wall of the bore of a distribution bar of the distribution system.
According to yet another aspect of the present invention there is provided a pastillation machine. The machine comprises: a first cylinder having a first end and a second end and an outer surface, the first cylinder being supported at the first end and the second end, a cavity formed in the first cylinder, the cavity being in communication with a source of a flowable substance, a slot formed in the outer surface of the first cylinder, the slot being located between the first end and the second end, fluid outlets located in the slot, the outlets being in communication with the cavity of the first cylinder, a second cylinder surrounding the first cylinder and being rotatable thereon, the second cylinder having rows of openings therein, a distribution bar sized to fit into the slot and being sandwiched between the inner cylinder and the outer cylinder, the distribution bar having an inlet surface and an outlet surface and a bore extending therethrough, a series of holes located on the inlet surface, the holes being aligned with the fluid outlets of the first cylinder for receiving the flowable substance therefrom, a series of slots located on the outlet surface, the series of slots of the distribution bar being in communication with the rows of openings in succession, and a diffuser located between the inlet surface and the outlet surface, the diffuser bar extending axially through the bore of the distribution bar wherein as the openings of the outer cylinder pass over the series of slots of the distribution bar, a predetermined amount of flowable substance passes through the openings and drops onto a moving conveyor located below the pastillation machine.
It is an advantage of an aspect of the present invention that the distribution system distributes essentially evenly the flowable substance to produce hemispherical pastilles having similar size.